Background:  Infants who present with a history of an acute event (an unexpected change in an infant's breathing, appearance, or behavior), reported by their parent or caregiver, represent a heterogeneous group of patients of varying ages with diverse pathophysiology. A BRUE is diagnosed only when there is no explanation for the described event after a thorough history and physical examination. Aim of the study: to detect the incidence of Brief Resolved Unexplained events and differentiate Risk Factors according to initial presentation of cases and follow-up. Methods: Prospective application of BRUE criteria on infants younger than 12 months old who presented to emergency room of Bab El Shaaria University Hospital from 1 June 2018 to 1 December 2018. BRUE patients were classified into Lower-risk (LR-BRUE) and Higher-risk (HR-BRUE). History was taken from all caregivers and all patients underwent physical examinations and o2 saturation monitoring by pulse oximetry on room air. Studied infants were followed up 3 to 6 months after discharge either by regular visits or by phone. Results: study included 2462 Infants below 1 years old, the inclusion criteria of BRUE met 39 patients ( 1.58%) 18 of them are males (46 %)  and 21 are females(54%), 23 of BRUE cases classified as low Risk BRUE(59%), and 16 cases as High Risk BRUE(41%) all were admitted for further investigations . prematurity was conducted in 9 cases (23%). The entire BRUE group was monitored by pulse oximetry for 4 hours, O2 saturation was above 90% in 36 cases (93%), while 3 cases (7%) were below 90% and all had been admitted for further assessment and investigations. The incidence of death was in 3 cases (8%) all of them was HR-BRUE. Recurrence occurred in 8 patients (10%) , 2 of them were initially classified as LR-BRUE. The most frequent diagnosis of HR-BRUE was pertusis in 4 cases (25%), GER in 3 cases (19%) and epilepsy in 2 cases (13%). Conclusion: Diagnosis of BRUE represent 1.58 % of the studied cases, the risk of Recurrence is statistically significant in patient below 2 months old , preterm infants , infants with history of underlying diseases , and those whose O₂ saturation above 90%. While the Risk of death was statistically significant in infants with history of underlying diseases, History of NICU admission and those who's presented by high Risk BRUE.